1. Field of the Invention
The invention relates to an apparatus for the removal of residues deposited on the inner wall of a pipe carrying hot gases and/or vapors.
2. Description of Related Art
An apparatus of the above-mentioned type is disclosed in Chem.-Ing.-Techn., Vol. 54, 1982, p. 382, FIG. 4. The disclosed apparatus comprises a driven shaft carrying different axially extending scraping devices for scraping off residues deposited on an inner wall, when moved radially. Both the center shaft and the scraper devices remain stationary inside the apparatus and are constantly exposed to the hot gases and/or vapors flowing through this internal space. The apparatus can therefore only be used within a temperature range of up to about 100.degree. C., as at higher temperatures the scraper devices would melt and would no longer be able to perform their function. The use of more temperature resistant materials, such as ceramics, for the scraper devices, in order to attain higher operating temperatures is not practical, as these materials have low mechanical strengths and are very difficult and expensive to use.